1. Field of the Invention
The present invention relates to an inkjet image forming apparatus. More particularly, the present invention relates to an inkjet image forming apparatus having an inkjet printhead that is refillable with ink.
2. Description of the Related Art
When ink contained in an inkjet printhead is used up, the inkjet printhead is replaced with a new inkjet printhead or is refilled with ink. An inkjet image forming apparatus includes an ink residual quantity detection unit, which detects the amount of ink remaining in an inkjet printhead. It is necessary to precisely detect the exact amount of ink remaining in the inkjet printhead to inform a user that the inkjet printhead needs to be replaced with a new inkjet printhead or needs to be refilled with ink. In a case where the inkjet printhead is refilled with ink with the image forming apparatus turned on, the ink residual quantity detection unit can recognize that the inkjet printhead has been refilled with ink. However, if the inkjet printhead is refilled with ink with the image forming apparatus turned off, the ink residual quantity detection unit cannot determine whether the inkjet printhead has been refilled with ink, in which case, the ink residual quantity detection unit may have imprecise information on the amount of ink remaining in the inkjet printhead.
Accordingly, a need exists for an image forming apparatus having a refillable inkjet printhead that substantially avoids refilling of the inkjet printhead when the image forming apparatus is turned off.